The present invention relates to an electrical contact element with a cover layer arranged at least on a contact section of the contact element, the cover layer being electrically conductive. Furthermore, the invention relates to an electrical contact arrangement with at least one electrical contact element and at least one counter-contact element for the electrical contact element, the counter-contact element being adapted to mechanically contact a contact section of the electrical contact element. Moreover, the invention relates to a method for manufacturing an electrical contact element by adding a cover layer, and to a method for reducing oxidization of a contact section of an electrical contact element.
Electrical contact elements are widely used to provide electrical connections with counter-contact elements. The contact elements may be plug or switch contact elements. Movements of the contact elements and/or the counter-contact elements relative to each other may cause mechanical abrasion of at least one of the contact elements and in particular, of a contact surface of the contact section of the respective contact element. Damage to the contact surface may lead to exposure of the previously unexposed electrically conductive material of the cover layer. The conductive material may be metal which oxidizes when in contact with oxygen, e.g. contained in air. The oxidized material may form a layer on the contact element especially in the area of the contact section. If the contact surface is repeatedly damaged, the oxidized layer may grow in thickness and impair the electrical conductivity, in particular, of the contact surface. This may lead to a malfunction of the electrical connection between the contact element and the counter-contact element.
Even if the contacts are not moved in the way described above, the contact section may be damaged. In particular, vibrations or movements caused by thermal elongation may cause damage in the contact surface.
Hence, the durability of the contact elements and of the electrical contact arrangement may be limited due to the decreasing electrical conductivity caused by the growing oxide layer thickness.
In view of these disadvantages of the known electrical contact elements, an object underlying the invention is to provide electrical contact elements with an improved durability.
The object is achieved according to the invention for the electrical contact element mentioned in the beginning in that the cover layer comprises a chemical reducing agent that is adapted to reduce metal oxides of the cover layer. For the electrical contact arrangement mentioned above, the object is achieved according to the present invention in that the contact element is formed according to the invention. For the manufacturing method mentioned above, the object is achieved according to the present invention in that the method comprises the step of embedding a chemical reducing agent in the cover layer. For the method for reducing oxidation, the object is achieved in that the method comprises the step of applying frictional forces to a cover layer arranged on the contact section and thereby releasing a chemical reducing agent.
These simple solutions provide that oxidization of damaged contact surfaces is during the operation of the contact element decelerated or even prevented and may even, at least partially, be reversed.
The solutions according to the invention can be combined as desired and further improved by the following embodiments that are in each case advantageous on their own.